Feature published in 3D ADEPT MAG in August 2018, then online in October 2020. Interviewees’ roles, projects and expectations reflect the interview period. Editorial clarifications explain the scope of the applications.
Universe Architecture’s Landscape House project, announced in 2013, helped draw attention to 3D printing in building. This 2018 feature examines the technology’s potential and the obstacles to its development.
3D Model Print, XtreeE and Apis Cor share their experiences, from architectural models to construction components. These applications face different constraints.
1. Architecture and Construction: two complementary sectors?
“Architecture consists in order (ordo), disposition (dispositio), eurythmy (eurythmia), symmetry (symetria), decoration (decor) and distribution or economy (distributio). Any work must be achieved while taking into account solidity (firmitas), usefulness (utilitas) and beauty (venustas).” Vitruvius, De Architectura, book I, chap. II, 1 and chap. III, 2.
This passage links aesthetics, use and strength: architectural design must bring them together within a project.
Drawings, digital models and physical models represent the project. Architecture organises design choices; construction implements them within technical and site constraints. The activities complement one another.
Architecture and construction: are they really complementary?
Paul Mournaud, a model maker at 3D Model Print, describes this relationship:
“Architecture is an art. Its aim is to imagine, think and design buildings and structures. In addition to analyze the social and environmental impact, the architect’s work should represent a philosophy and unveil beauty.
Construction on its side, allows the fabrication of these buildings and structures.
Architecture enables construction and construction needs architectural reflection. Both sectors are complementary for the complete implementation of a physical and sustainable project. Architectural representation can be achieved without its final fabrication – construction- but it will remain an unfinished concept, that has just been drawn on a sheet of paper. However, construction might require a little bit of architecture because one cannot build without preliminary reflection.”
However, if 3D printing is used in both architecture and construction, Alban Mallet, President of XtreeE, a 3D printing technology company specialized in architectural design, engineering and construction, highlights the need to recreate a relation between the two sectors and 3D printing in order to ensure cohesion in projects:
“Architecture and construction should be reconsidered in order to allow a better integration of technology into architectural design. The architect must have all the keys to address the issues of 3D printing; he should master the potential, the capacities and the limitations of 3D printing in order to know how he can adapt it to the technology. Once these competences will be acquired, his work will be more in line with the manufacturer. Therefore, the key relies in the ability to fill the gap between the architect and the construction when it comes to 3D printing technology.”
2. 3D printing in architecture
If the use of 3D printing in architecture includes several stages of a project development, its primary objective is to facilitate the understanding of a project. Indeed, even if they do not always realize it, architects’ drawings cannot be read as easily as a book and require a certain experience to visualize a 3D idea from a 2D diagram.
According to Paul Mournaud, the 3D printing process of an architectural part is made up of 3 main stages:
- Identify the type of fabrication that will be carried out. Is it a prototype? A model or a representation of an existing structure?
- Determine the required elements for the manufacturing of the part: type of machine, scale, materials and finishes.
- Once these data are set up, the architect should keep in mind that the 3D model will be subject to some constraints imposed by 3D printing, therefore adjustments will be applied depending on aforementioned settings.
Scale, machine, material and finishing choices guide preparation of the digital model. Details may need adjustment for resolution and strength. A model helps represent and discuss a project; it is not necessarily a construction prototype to reproduce unchanged. Desktop or industrial equipment can be used according to the requirement.
3. 3D printing in construction
At construction scale, 3D printing can produce components or deposit material directly on site. The constraints then concern materials, structure, connections and manufacturing conditions.
Vaults and complex forms illustrate the importance of construction expertise. 3D printing can offer alternative fabrication routes for some geometries; their stability and execution need to be studied whatever process is chosen.
A research roadmap published in 2018 distinguishes component production from printing walls in situ, with different constraints for each.
What are the challenges of 3D printing in construction?
For Anna Chenintai, Head of PR and Marketing at Apis Cor, construction 3D printing has highlighted four main challenges:
“The possibility of printing buildings in an uncontrolled natural environment. To compete with traditional construction, 3D printing should be performed directly at the construction site without additional protective constructions for the printing process. The solution of this problem lies not only in the mechanics of the printer but also in the field of building materials, i.e. the development of appropriate materials for 3D printing.
The printer should be maximally autonomous and work “with the push of one button”. At this moment, our printer is a sophisticated tool and it can be used only by properly trained people. This approach is very difficult to scale, especially in the construction industry.
The printing horizontal surfaces. In plastic 3D printing, this problem resolves by printing the support props. However, such method in the construction 3D printing would be economically impractical, because the concrete supports would have been dismantled instead of plastic. The printing of horizontal surfaces opens the possibility to print ceilings and roofs. Our team is working on it and we will present the first prototype soon. We already have a certain experience of printing of basement, but the question about automatic reinforcement to provide the required bearing capacity remains on the table for all the horizontal structures.
The development of standards for the design and analysis of printed structures and buildings. Professionals who are now busy designing buildings and constructions, need to have the regulatory framework and associated software to calculate the future printed structures made from different materials. Nowadays, the design and adaptation of projects under the requirements of the construction 3D printing take a very long time.”
Editorial clarification: these remarks describe challenges discussed in 2018. Printing a wall or component does not mean an entire building, including foundations, floors, roof and services, is printed. Structural design and verification remain project-specific.
Control of the material, its flow and setting is therefore central to the process.
Materials used in construction 3D printing
Alban Mallet brings out the advantages and the limitations of 3D printing materials used in the construction industry. XtreeE is used as illustration to bring out these main points.
“XtreeE mainly works with cement and concrete. It is a high resistance mortar which allows for the manufacturing of solid structures. We also work with clay and earth. Those materials enable us to achieve shapes that cannot be made with 3D concrete printing directly. Once complex moulds are manufactured, the clay is thereafter removed and inserted into the machine for reuse and this is a good advantage in terms of environmental impact.
However, one limitation of clay is that it requires too much time to dry. Furthermore, its use requires a lot of time in terms of manufacturing. Further research should be carried out on clay in order to propose solutions with shorter manufacturing times.
We also work with polymers: PE, PEHD, polyethylene… even though they are different from clay, they also present advantages and disadvantages. As far as advantages are concerned, they are easy to use and can make shapes that cannot be made with clay or concrete because it dries very quickly. However, in terms of environmental footprints, plastic is not always the most appropriate material. Moreover, one should know exactly the most appropriate place to use it.
In terms of research and development, we are analyzing the possibility of using steels and metals.”
Terminology clarification: PE means polyethylene and HDPE its high-density form. An extruded thermoplastic solidifies by cooling, distinct from clay drying or the setting of a cement-based material.
What are the considerations one should take into account in the development of materials?
Once these materials are defined, it remains important to know the parameters that should be taken into account in the research and development of new materials. Sergey Nefedov, Head of Department of Technological Development at Apis Cor mentions 3 parameters in the development of materials for 3D printing:
“Rheological characteristics such as mobility, preservation of initial mobility, lifetime of the mortar and timing of its setting. These parameters are determined by the design of the 3D printer and the length of the alignment print.
Physical and mechanical characteristics. They are defined for a specific project based on the need of providing the wall structures that will bear capacity and geological features of the area.
Technical and economic parameters. Since our ultimate goal is to provide affordable housing to as many people as possible, we intend to develop a mix based on the local raw materials with a minimum cost that will enable to achieve the rheological and physical characteristics.”
For its part, Apis Cor works with geopolymers and has developed a range of materials based on mineral raw materials. However, Sergey Nefedov mentions that they “require hardware setup. Some materials, such as geopolymer, require changes in the mixing system. At the moment, we see tremendous opportunities for the use of any materials for 3D, but we realize that in order to use these types you need to enhance equipment. For now, the only limitation for us is the grain size of the filler. While we only work with fillers whose maximum grain size does not exceed 5 mm, we continue to work on removing any using restrictions of different materials.”
4. What about the prospects of development?
In the applications discussed, 3D printing offers geometric and automation opportunities. Their value needs to be compared with other fabrication methods for the specific project.
The interviewees see a possible route towards more industrialised production of selected construction elements.
This approach brings together materials, architecture, engineering, research and digital tools including BIM. It requires coordination across disciplines.
From an environmental point of view, Sergey Nefedov explained that the use of 3D printing in construction will “significantly reduce the amount of construction waste. Thanks to the machine precision you build the walls once in the desired shape and you do not use the excess material. In this case, there is no need to cut the piece elements and to do additional processing of the walls.”
Editorial clarification: waste reduction is a potential benefit that needs to be measured. It does not alone establish a building’s environmental performance, which also depends on formulations, material quantities, energy, transport and service life.
However, even though some professionals really consider the use of 3D printing for social housing or for other geographical environments, the truth is that the technology is not yet mature in this sector and requires a lot of investment and tests in order to be used in mass production. As Anna C. said: “Every new technology is always expensive at the beginning of its path, [therefore] requires a lot of resources for the implementation of each new project.”
5. 3D printing in architecture and construction: Advantages and Focal points
| Application or issue | Potential discussed | Condition or consideration |
|---|---|---|
| Project understanding | Make volumes and spaces easier to understand | Coordinate architectural representation with construction constraints |
| Physical models | Present form and appearance | Adapt scale, details and finishes |
| Complex geometry | Explore alternative forms and fabrication routes | Assess feasibility, stability and cost |
| Local context | Adapt solutions to the site and available resources | Qualify formulations and invest in R&D |
| Environment | Reduce selected waste streams and material use | Compare the full life cycle without assuming a benefit |
| Site organisation | Automate selected tasks and reduce some lead times | Provide trained staff and account for operations that are not printed |
Conclusion
A printed model helps communicate a project, but requires decisions on resolution, scale and finish. Producing components for a building adds structural, durability and site-integration requirements.
The 2018 feature raises a useful question for assessing a project: which gains are demonstrated, for which operations and at what total cost? Housing affordability cannot be inferred from wall-printing time alone; it depends on the complete build.
This feature was first published in the August Issue of 3D ADEPT Mag (2018).
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